The stitches which form the pinpoint stitch appearing and disappearing on one side of a fabric workpiece alternately by one sewing thread and project an atmosphere of the handstitch is standardized as ISO 4915 Stitch Type 104 (chain stitch) and ISO 4915 Stitch Type 209 (saddle stitch/handstitch) of the international standard.
Heretofore, a pinpoint stitch sewing machine which forms “104” stitch as the pinpoint stitch (quasi-handstitch) and prevents a cloth misalignment of such a pinpoint stitch sewing by using the sewing needle that one sewing thread which is pierced to the needle is pierced, an open eye needle that the thread capturing open eye is equipped laterally, a looper and a spreader is known (for example, refer to Patent document No. 1).
Because this pinpoint stitch sewing machine uses the sewing needle that one sewing thread is pierced and the open eye needle that the thread capturing open eye is equipped laterally, there is a disadvantage that a stitch length is limited to a distance between the sewing needle and the open eye needle. And, in this pinpoint stitch sewing machine, when sewing, a balloon stitch is formed on the upper side of the cloth. However, because the pinpoint stitch to be stitched intrinsically is formed in the lower side of the cloth, sewing work is forced to in the state that it cannot watch for a worker. Therefore, it is difficult to confirm the position of the pinpoint stitch and there is also a disadvantage that an exact sewing is not possible. Besides, in the “104” stitch of this pinpoint stitch sewing machine, because the stitch comes loose easily by pulling the sewing thread which forms the stitch, there is also a disadvantage that a function to prevent the above described cloth misalignment of such the pinpoint stitch sewing is lost.
In order to solve these disadvantages, the quasi-handstitch sewing machine which forms a quasi-pinpoint stitch similar to the “104” stitch by using the open eye needle that one thread capturing open eye is equipped laterally, a thread grapple hook, a guide spreader of the sewing thread to the thread capturing open eye and a thread take-up lever by one thread which is wound around a bobbin arranged in an inside of a rotary hook is proposed (for example, refer to Patent document No. 2).
Patent document No. 1: Toku-Kou-Shou 55-35481 (FIG. 5, FIG. 6, FIG. 7)
Patent document No. 2: Toku-Kou-Hei 4-3234 (=U.S. Pat. No. 4,590,878) (FIG. 11, FIG. 13, FIG. 14)